Allergy

Hives (Urticaria) Program

Hives are a common skin condition that may occur in as much as 10-15% of the population at some time in their lives. The skin outbreaks (or lesions) can have a variable appearance but they are almost always itchy and red. At times there is a “wheal and flare” response, with a raised pale swelling 1/8 to 2 inches in diameter surrounded by a red flare. At other times the skin outbreaks consist of lesions that are raised and red all over. Individual lesions can come and go over several hours or last for several days. Excessive scratching can cause a breakdown of the skin and the formation of scabs.

Hives can occur on all parts of the body but in certain areas they tend to have a different appearance. On thick skin (such as the palms of the hands, soles of the feet, or scalp) they can be itchy or even painful with a swelling that is less well defined. On soft areas of the skin such as around the eyes and mouth or on the genitalia, all that often occurs is a poorly circumscribed swelling without the discrete red areas (this is called angioedema by doctors). There is another group of diseases that go by the name “angioedema” in which there is a localized swelling without redness or itchiness (this can be hereditary or caused by a class of blood pressure medications called “ACE inhibitors”).

Sometimes hives can involve non-skin areas of the body such as the tongue and back of the throat. This is a potentially dangerous and requires special precautions. As a rule if the hives have been present for a number of weeks and involvement of the mouth has not occurred it is unusual that they would spread to this location. Rarely hives can involve the stomach and intestines and produce nausea, cramps and diarrhea. What makes hives confusing to patients and doctors alike is that hives can change the way they manifest themselves over time.

Foods
A number of foods commonly cause hives (these include tree nuts, peanuts, various kinds of seafood and fresh fruit and vegetables). As a general rule the hives follow food ingestion by less than an hour. Hives that do not bear a consistent relation to eating probably are not related to foods.

Drugs
Generally drugs cause hives in a person that has had a previous (sometimes remote) exposure to the drug in question. The hives following ingestion of or injection with a drug can be very severe and rapid in onset. As a general rule, if a person has taken a drug for more than two months, then it is unlikely it is the cause of the hives. Hives can develop the first time that a person takes a drug but they usually start after a delay of 10 to 14 days (this is called primary sensitization). It should be noted that drugs commonly cause skin reactions other than hives.

Contactants
Local exposure of the skin to an allergen can cause hives (such as touching grass or animal hair). This form of hives invariably comes on within minutes and is localized at the site of contact only.

Insect stings
Hives can follow a sting by less than 1/2 hour.

Exercise
There is an unusual form of hives that is brought on only with exercise. Exercise will also aggravate other forms of hives. If exercise is the only trigger then anaphylaxis can also occur.

Physical urticarias
Very specific physical stimuli such as ultraviolet light, vibration of the skin or cold exposure can cause hives in some people. Rarely a reaction to a drug can cause a type of physical urticarial.

Aggravating factors
One or more factors can aggravate the hives in a given individual but are not the basic cause of the condition. People who are having intermittent hives will sometimes experience an aggravation when there is an increase the blood flow to the skin (heavy exercise, hot showers). Any kind of stress can aggravate preexisting hives but stress is rarely if ever a causative factor. In some people, hives occur along pressure points such as belt lines. Scratching will at times bring on the hives and in this case a linear swelling occurs along scratch lines (If scratching is the major precipitant the condition is called “dermatographism”).

Evaluation

During your evaluation, your doctor will take a careful history and then do an examination. Skin tests may occasionally be ordered if allergic factors are considered possible.

Rarely, systemic diseases are associated with hives and if your hives have been present for more than several months your doctor will probably do some blood tests to rule out these conditions. Occasionally a skin biopsy is done if the appearance of the hives warrants this procedure. Factors that are specific to your situation will dictate what kinds of tests your doctor orders.

Treatment Options Available

The treatment plan that our allergists create for you usually consists of various kinds of antihistamines and in severe cases short courses of cortisone pills or other kinds of drugs that suppress the immune system. Your doctor may proscribe different combinations of drugs until an effective treatment program is achieved. None of the medications that are used for hives are curative; they just suppress the symptoms and make the hives more tolerable. If a cause can be found then removal of the cause is the best treatment.

Topical creams are almost never effective because the origin of the hives is too deep in the skin for a topical medication to have any chance of success. Alcohol based creams may have a temporary effect in reducing itching but the effect is too short-lived to be useful.

For chronic urticaria, the purpose of treatment is to make your life tolerable until the hives run their course. If you are prone to swelling of your mouth or throat then you may be prescribed an adrenaline injector for emergency use.